Steel mills

A steel mill or steelworks is an industrial plant for the manufacture of steel.

Steel mill can refer to the steel works making rolled products from iron ore, but it also designs, more precisely the plant where steel semi-finished casting products (blooms, ingots, slabs, billets) are made, from molten pig iron or from scraps.

Since the invention of the Bessemer process, steel mills have replaced ironwork, based on puddling or fining methods. New ways to produce steel appeared later: from scraps melted in an electric arc furnace and, more recently, from direct reduced iron processes.

In the late 19th and early 20th centuries the world's largest steel mill was the Barrow Hematite Steel Company steelworks located in Barrow-in-Furness, United Kingdom. Today, the world's largest steel mill is in Gwangyang, South Korea.

An integrated steel mill has all the functions for primary steel production:

The principal raw materials for an integrated mill are iron ore, limestone, and coal (or coke). These materials are charged in batches into a blast furnace where the iron compounds in the ore give up excess oxygen and become liquid iron. At intervals of a few hours, the accumulated liquid iron is tapped from the blast furnace and either cast into pig iron or directed to other vessels for further steel making operations. Historically the Bessemer process was a major advancement in the production of economical steel, but it has now been entirely replaced by other processes such as the basic oxygen furnace.

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